Cell imbalance when using reference design for BQ40z50

I've got a dozen packs that all have low voltage on cell 1. Every single pack has ~2700mV for cell 1 and ~3200mV for cells 2, 3 and 4. The packs are Lithium Iron Phosphate cells, four cells each. Learning cycle has been completed and we have the correct Chem ID in place. All packs show RSOC between 60 and 90 percent. The schematic for the fuel gauge is pulled directly from the reference design with no significant changes. I would ordinarily put this down to a bad cell, but it's cropped up on Cell 1 of 12 packs. It is highly improbable that the same cell in each of 12 packs would be faulty in exactly the same way. I've also checked the boards and there are no shorts or other defects which would cause cell 1 to discharge faster than anything else. What is happening with Cell 1? Is there some additional draw on it in through VC1 that is not specified in the reference document? Any assistance would be greatly appreciated.